It is widely recognized that digital communications technology and data processing technology are converging. One example of this is the development of portable personal computers that include telephone modems, enabling the transmission of digital information over public switched telephone networks. Another example is the development of mobile radio telephones that use microprocessors executing stored programs for sampling and digitizing the voice signal, multiplexing the transmission of the digitized voice signal with other such voice signals, and digitally controlling the operations of the cellular telephone device.
The most recent evidence of the convergence of digital communications technology with digital personal computer technology, is the SIMON personal communications device announced by the IBM Corporation in 1994. The SIMON personal communications device has many features within it to enable personal communications. The personal communications device provides a cellular telephone, a facsimile transmission and receiving capability, an electronic mail sending and receiving capability, and an electronic pager, a computer notepad, a computer address book, a computer calendar, and a computer calculator, all within a single compact portable package.
The SIMON personal communications device includes a central processing unit (CPU) that executes stored programmed instructions stored in electrically programmable read only memories (EPROM). The stored program instruction in the EPROM's include basic input output operating system (BIOS) programs, and application programs to perform the functions of cellular telephony, public switched telephone network (PSTN) telephony, facsimile transmission and reception, electronic mail, pager functions, computer notepad functions, computer address book functions, computer calendar functions, and computer calculator functions. These stored programs are selectively transferred from the EPROM's to a read/write random access memory (RAM) for storage and execution by the CPU.
The SIMON personal communications device also includes a display having a touch overlay membrane, to enable the user to input keyboard entries in the for of tactile pressure with a finger or a stylus.
The storage capacity of the RAM can be augmented by employing supplementary memory in the form of a personal computer memory card (PCMCIA) (Trademark of the Personal Computer Memory Card International Association). The personal computer memory card can include extra RAM to supplement the RAM storage in the personal communications device, by plugging the personal computer memory card into a PCMCIA receptacle slot in the personal communications device.
The rapid advance in the technology of computer programming, data processing functions and communications functions, dictates the frequent revision of the computer programs used in high function systems such as a portable computer or the SIMON personal communications device. However, the techniques to reprogram EPROM's require accurate, painstaking steps to accurately erase only those portions of the stored programs that need to be replaced and to accurately substitute the new programs in the device. The requirement for accurate, painstaking care in the reprogramming of the EPROM's, makes the upgrading of computer programs in a portable personal communications device or in a portable computer an unsuitable job for the casual user.